15x2 +x -14 = 0
ax2 bx c = 0
a = 15
b = 1
c = -14
Δ = b2-4ac
Δ = ² - (4 * 15 * -14)
Δ = 1 - (4*-210)
Δ = 1 - (-840)
Δ = 841 Δ > 0
15x2+x-14=0
x = -b ∓ √Δ 2a
x' = -1 - √841 2*15 = -1 - 29.0 30 = -30.0 30 = -1.0
x" = -1 + √841 2*15 = -1 + 29.0 30 = 28.0 30 = 0.933333333333
x' = -225.0
x" = 210.0
S = {x ∈ R / x' = -225.0, x" = 210.0 }